Medical staple forming die and punch

Abstract

A medical staple forming die and pusher punch for use in a staple forming machine. The bend radius of the staple is formed either by the form punch pushing the wire past a set of rollers, or by movable forming dies in conjunction with a tapered or contoured pusher punch. Since the wire is not scrapping on a stationary rail, pulling thin or cracking in its corners is substantially eliminated and the possibility of metal slivers produced by the prior art scrapping methods is substantially reduced or eliminated.

I claim: 
     
       1. A forming punch having particular utility to facilitate the forming of a new and improved medical staple having a pair of spaced apart projecting leg portions (92, 93) each with a relatively gradual bend portion (97) defining a desired radius of bend curvature (77) with a base member (91), comprising: a body portion (72); and   a head member (73) integrally formed with said body portion, and having tapered wall portions (78) defining a relief angle (79) of taper, and a tip portion (74) with a pair of transverse side wall members (76) and an upper transverse channel wall member (80) defining a transverse staple wire receiving groove (75), said upper transverse channel wall member (80) having upwardly curved end portions (77) each defining a predetermined radius of bend curvature substantially similar to the desired bend curvature of the medical staple bend portions (97).   
     
     
       2. A forming punch as in claim 1, wherein: the body portion (72) comprises an elongate flat rectangular shaped metal rod.   
     
     
       3. A forming punch as in claim 1, wherein: the staple wire receiving groove (75) being dimensioned for snugly receiving and holding a preselected staple wire (44) dimension.   
     
     
       4. A forming punch as in claim 1, wherein: the relief angle (79) of taper being predetermined relative to the dimension and type of the medical staple being formed.   
     
     
       5. A forming punch as in claim 1, wherein: the radius of bend curvature (77) is predetermined to define and control the bend portion (97) curvature of the medical staple (90) to substantially reduce cracking and thinning of the medical staple at the bend portion (97).   
     
     
       6. A forming punch and die, in combination comprising: a pusher type forming punch (70) having an elongate body portion (72) and a head member (73), said head member having a tip portion with a pair of spaced apart side wall members (76) and an upper wall member (80) defining a contoured staple wire receiving groove (75), said upper wall member having curved end portions (77) each defining a selected radius of bend curvature; and   a forming die (60) having a pair of spaced apart rail members defining a die cavity (64) and a pair of movable glide members (62, 103, 104), said die cavity being dimensioned for receiving therein portion of said forming punch.   
     
     
       7. A forming punch and die as in claim 6, wherein: the forming punch has a generally elongate flat rectangular configuration with said wire receiving groove being concave and extending transversely across said tip portion and having a predetermined radius of curvature.   
     
     
       8. A forming punch and die as in claim 6, wherein: the head member has inwardly sloped wall portions (78) defining a relief angle (79).   
     
     
       9. A forming punch and die as in claim 6, wherein: the glide members each comprise a roller (62) rotatably mounted to a respective rail member.   
     
     
       10. A forming punch and die as in claim 6, wherein: the glide members each comprise a cam (107) having a concave section (116) and a nose section (114) and a hell section (113), rockingly mounted to a respective rail member.   
     
     
       11. A forming punch and die for forming a metal wire strip (44) into a medical staple (90) to have relatively parallel staple legs (92, 93) substantially without metal wire cracks (48) along a relatively gradual wire bend curvature (97), in combination comprising: a pusher forming punch having a body portion (72) and a head member (73), said head member having tapered side wall portions (78) defining a predetermined relief angle (79) of taper, and having a contoured tip portion with a pair of spaced apart transverse and downwardly projecting wire retaining wall members (76) and an upper transverse curved ceiling wall member (80) defining a transverse staple wire receiving groove (75), said ceiling wall member having upwardly curved end portions (77) each having a curvature for constraining the metal wire strip about the wire bend curvature (77) to substantially reduce any cracking and thinning of the metal wire strip while forming the medical staple (90); and   a forming die (60) having a pair of spaced apart rail members each having an upper bevelled edge corner (61), and a pair of aligned roller means (62) each rotatively mounted to a respective rail member and projecting outwardly beyond the respective die walls (63) which define a die cavity (64), said aligned roller means being spaced apart a distance to enable disposition of portions of said pusher forming punch, whereby with the metal wire strip (44) being positioned longitudinally within said wire receiving groove (75) and with said pusher forming punch being urged between said roller means (62), the outwardly extending metal wire strip on both sides of said head member are bent over the respective curved end portions (72) of said pusher head member for effecting the gradual wire bend curvature (97) of the staple legs (92, 93).   
     
     
       12. A forming die assembly having particular utility for forming a metal wire strip (44) into a medical staple (90) to have relatively parallel staple legs (92,93) substantially and relatively without metal wire cracks (48) along a relatively gradual wire bend curvature (97), comprising: a punch block (123) having a projecting mounting beam (130), a a stripper block configured for being mounted on said mounting beam (130), a first forming die member (118) slidably mounted unto said mounting beam (130) in slidable juxtaposition between said stripper block and a cut-off die 128);   a probe block (124) having a projecting mounting beam (131) and being spaced from and aligned with said punch block to define a die cavity, a probe sending block (126) configured for being mounted on said mounting beam (131), a second forming die member (119) slidably mounted unto said mounting beam (131) in slidable juxtaposition between said probe sending block (126) and a probe receiving block (127) in spaced alignment with said first forming die member;   a first spring means (122) for biasing said first forming die member (118) inwardly into said die cavity;   a second spring means (122A) for biasing said second forming die member (119) inwardly into said die cavity toward and in alignment with said first forming die member.   
     
     
       13. A forming die assembly as in claim 12, including: a pusher forming punch (70) having tapered side walls (78) and a contoured tip portion (73).